Projection of light



Oct. 16, 1934. HARKNESS r AL 1,977,477

PROJECTION OF LIGHT 2 Sheets-Sheet 1 Filed Dec. 21, 1931 M Inventors Fig. 3.

.dttorney- 1934- G. K. HARKNESS El AL 1,977,477

PROJECTION OF LIGHT Filed Dec. 21. 1931 2 Sheets-Sheet Attorney.

11 z 1 1 I 1 1 4 /1-6 4/0 I Fig.6

/1 1/ l zz ll ,1

Patented Oct. 16, 1934 7 f-UNIT ED srAre-s 1,977,471 v .rnomcsrrona OF ;LIGHT George. Kette'lwellfHarkness, Rochester; andflohn 'Mamvfell Harkness, Dartford; England, assign- "0T5, "by mes'ne assignments, to Berth old 1A.

Cronson Application December. 21; 193LQSei-iaI No.l-582.414 a J. I v.In@GtreatBritainJuly-11,1931 v .This' invention relates to"the="proiection:eand transmission of light; and has forrits' obj ect to provide improved means' 'whereby the:projecte'd or transmitted light may be controlled in intensity or colour. "The invention, 'while' of? broad application is especially applicable to'anti-dazzle or dimming .devices for the lamps or .-.wind., screens:of :motor vehicles or. aircraft. .Accordin'gto the inventionthe light which .is to be controlledtinintensity or colourv is projected or transmitted through juxtaposed plates of transparent material. suchias r glass, which plates are'mounted to permit.their'rseparation to at'determined or variable] degree for the formation-be- .tween the adjacent :surfaces'of a'cavityor'cavities into .which is introduced" a liquid or gaseousme- 'dium adapted to obstruct the passagetof: lightto a determined degree .or to impart a colour to light transmitted through it. According to thelinvention, moreover, the plates @may be;:mounted "with an initial-separation: providing between the adjacent surfaces .a cavity'of a thickness such thatwheniit is'filled'hy the liquid Nor gaseous medium a determined :maximum obstruction 1 on: colouration of the transmitted light is secured. According to: thelinvention; a1so,:.a .pluralityzof pairs of: such platesimayfbe juxtaposedz :for the transmission of the light through them insucces- ..-sion, andzthe liquidsori gaseousrrmedium :may: be caused to pass between theplates of any onerpair or of more than: one. pairrsimultaneously forathe *ob'structionbof the transmitted? light: to a-determined degree,'o'r to: impart to thetransmitt'ed 1 light any desired colour. or combinationcoficolours. According to the. invention, -rmoreover;:certain 1 or. all iofrithe transparent: plates maybe-provided in the formzof lenses. 1 .Accordingto the invention,*moreoveriiit iswaLdvantageo'us .to employaas theiobstructingimedium :a liquid orsolutionof low freezing: pointrsuch' as alcohol. g

According to' the invention, also; 'the;:introduction of the liquid or" gaseous medium:betweenthe plates of thepair or pairs of platesmaybe effected under. pressure exertedupontheliquid or; gaseous medium to a variable degree, :according to the desired intensity of. colour: tobenimparted to? the transmitted light.

According to the invention, r moreover, "means may be provided for causing thea'dm-issi'onuor withdrawal of' the" liquid or-"gaseous medium to and from the cavity'or cavities-between theplates,

comprising a flexible diaphragm -or*pistonithat by way of example in theaccompanying drawings.

ing the application of theuinvention'as .anaan-tider the action of a spring ornlike operating element, whereby, upon amovement of the -diaphragm or. piston in one direction; the contents,

or part of the contentsiofta container may vbe. forced into the cavity'vor cavitiesrbetweenthe plates, or be immediately withdrawn onthe. re-

- turn movement of thetdiaphragmor piston.

The invention .is :diagrammaticallyillustrated Figure-1..is a: crosses'ection of a vehicle wind screen constructed according to the :invention;.the transparent-z plates: being shown: in contact :or; in the inoperative position.

Figure. 2 is a cross-section ofthe vehicle wind :maynbea adaptedi for. instantaneous operation .un-

screen shown in- Figure l, "withxthe transparent plates separated by the liquid medium.

- Figure 3 isapartial front elevation of the :wind

' screen shown inzFi-gures 1 and 2.

dazzle or dimming devicettothe: head lights; of

.motor vehicles.

. Figures 6,. 7s'and 8iareicross-sectional'.viewsof modified arrangementsaof the transparent; plates of the apparatus-according to the invention.

In carrying the invention into efiect-inthe' production of l a wind screen foramotor vehicles in the manner illustrated in Figures 1 1130301; the accompanying drawings; a'pair. of "plates at ofiglass are mounted inj uxtaposition in :a :rubber seating b carried in a framing"c ofemetalzworaothersuitable'material. "The platesz'a are bevelledalongthe inner or adjacent edgesza'sxat asoi that. aacavity of triangular cross-section is formed around the outer edge. iI'he rubber seatingsisnfonmedi ad- H 'vantageously as man vopen rectangular ---body z or annulus of rubber adapted to be ifittedxwithinthe channel section: of the 1 frame: ciand: having, on

the inner face grooves :01" channels I5 1 *moulded or otherwise provided of a 'cross sectional shape corresponding to that of theperi'pheral sedgesof the transparent plates; but: with: the ima-terial intermediate the grooves or channels cut awayto leave a cavity (1 of triangular section-between the bevels of the plates when theyare: in position within the seating. 'Therubberi-seating is; moreover, provided of .a'material havingqaiconsiderable degree rof elasticityithatwillr permitrlthe separation of the'ipl-atesiundera relatively-lowvpressure p as exerted byraifluid-amedium introduced between the said plates. To facilitate the movement of the plates the inner surface of the rubber seating is bevelled or cut away at the lateral edges as at b so that the resistance offered to the movement of the plates is thus reduced, since the rubber may extend outwardly in the direction normal to the plates to fill the spaces or recesses 12 At one or more points along the upper limb of the rubber seating b there are provided inlet passages 12 which are connected by rubber conduits b leading outwardly from the frame 0 and connected to a suitable reservoir of a liquid medium which can be subjected to the necessary pressure to force the liquid by way of the passages 22 into the cavity d and thus between the plates a, whereby the plates are separated to the extent determined by the pressure exerted by the liquid and the windscreen is clouded or coloured to a corresponding intensity according to the nature of the liquid used. Thus, the liquid may be a transparent violet liquid which in athin film, as determined by close adjustment of the plates a, exhibits a slight trace of violet colouration, whereas, when the plates are moved apart to a greater extent and the body of liquid present is of. greater thickness, the colouration is of correspondingly greater intensity.

Any-suitable device may be employed for the purpose of exerting the pressure necessary to force the'liquid medium between the plates at. Thus, asimple plunger device may be provided in which the plunger is operated by a hand lever or the like, or the plunger may be adapted to be operated by a screwed controlling member, whereby any degree of pressure may be exerted through the'plunger upon the-liquid to be introduced be tween the plates. A preferred form of pressure device is illustrated inthe accompanying drawings in Figure 4. A cylindrical container or reservoir e for the liquid medium is mounted at a convenient position, for example, upon the dash board of the motor vehicle. The upper end of the said container is closed by a flexible diaphragm ,f which is clamped at the periphery upon the'end of the container by a downwardly deseated a dished plate spring or leaf spring g.

The said spring is secured at the centre to a control rod g which extends through a guide sleeve e in the cover plate 6 and is provided at the outer end with a knob or handle g At the inner end the rod 9 is engaged with the. diaphragm by means of a pair of washers f f ,.between which 'the material of the diaphragm is engaged and secured in position by such means as nutsg screwed uponthe rod 9 Such a device is adapted fol-instant control, since when the knob or handle g has been pressed inwards to cause the spring g to be deflected past the dead point,

the consequent movement of the diaphragm f continues notwithstanding the withdrawal of the hand from the knob 9 There is thus produced what may be termed a prolonged pumping action neous.

while the operation is substantially, instanta- Under the pressure exerted by the diadead point on the outward stroke.

phragm it will be understood that the liquid contained in the container e is forced into the cavity d surrounding the plates a and under the pressure exerted passes between the plates. thus providing the desired dimming effect. When it is desired to restore the plates to the inital position without liquid between them, it is only necessary that the knob or handle 9 should be withdrawn until the spring 9 has again passed the The liquid is then withdrawn from between the plates a under the suction imposed by the diaphragm g. Such diaphragm device may be used either as a suction or pressure pump for the pumping of liquids or gases generally.

The frame 0 isconveniently mounted upon the usual standards orsupports c by such means as rods 0 which are received into a tubular member 0 fitted around or forming part of the upper limb of the frame 0. The position or angular adjustment of the windscreen is determined by adjusting screws 0 adapted to engage the rods 0 Figure 5 of the accompanying drawings illustrates the application of the invention as an antidazzle device to the head lights of motor vehicles. The head lights h are provided in the manner before described, in place of or in addition to the usual front glass or lens, with a pair or pairs of plates such as a to which a liquid medium is supplied by way of a conduit h from the pressure device 6 mounted upon the dashboard.

It will be understood that while in certain ap-- plications of the invention it is desirable to maintain the transparent plates with their adjacent surfaces initially in contact, it may be desirable in certain applications to maintain them with a determined initial distance or space between them and to permit such space to be increased in width upon the introduction of the liquid or gaseous medium into the said space.

According to a modification of the construction as illustrated in Figure 6 ofthe drawings, in the place of the pair of plates a hereinbeforedescribed, there may be provided two plates 2' suitably mounted in fixed positions in the carrying framed, and a third plate is which is movable within the space between the plates i,,being supported by a flexible rubber or like seating 2. Liquid may be supplied to the exterior of the said seating by way of a conduit m and may enter into the space between one of theplates i and the plate k by way of an orifice or orifices Z so that the-desired colouration or obscuring of the light transmitted through the plates is secured to a degree that is determined by the volume of liquid or gaseous medium forced into the said space and the consequent movement of the plate It from its middle position towards the second plate 1'. Such a construction, however, may be modified by dividing the cavity around the exterior of the seating 1 into two compartments, one of which communicates with the space between the plate It and one of the plates 1, and the other of whic'h'communicates with the space between the plate It and the other plate 2. If the said compartments are respectively connected with containers of liquids of different characters, the device may be employed either for imparting one or, other or both of two colours to the transmitted light, or for imparting on the one hand a colour to the transmitted light or for obscuring the light to a greater or less extent.

In theuse of the apparatus according to the invention for advertising or for the production of stage. or screen lighting effects, a construction:

such -as that diagrammatically illustrated in Figure "7 may be employed. In this construction a series-of pairs of plates 0. such'as thosedescribed with reference to Figures 1 to 3 are set co'axially in a common frame 11,, and the cavity d surroundingeach pair of plates communicates by a corresponding conduit 0 with a container'containing a liquid'of a particular colour or character, each of the said containers beingprovided with a pressure producing device such as that hereinbeiore described, or being connected to some other convenient source of pressuresuch as a pump in such manner that any one or other of the containers may be subjected to the pressure either individually orcollectively. By such means any one or other orany combination of the pairs of plates 0. may be flooded with the corresponding liquids, with consequential colouration or other effect upon the light transmittedthrough the series of pairs of plates. v

' It will be understood that any convenient and suitableliquid or gaseous medium'may be used for-the purpose of the invention. In the application, however,- ofthe device to such purposes as the windscreens and head lamps of motor vehicles, it is desirable that a liquid or solution of low freezing point, such as alcohol, should be used. It will further be understood that it is immaterial to the invention whether the containers for the gaseous or liquid medium'be adjacent to the pairs of transparent plates or otherwise. It is also possible for the control to be effected from a distance by mechanical, electrical hydraulic or pneumatic means. Such distant control is especially desirable in the case of the application of the invention to stage or screen" lighting effects. It will furtherbe understood that the invention is'not limited to the particular constructions and details of construction hereinbefore described. Thus, instead of providing pairs of plates each of which is capable'of movement, one of the said plates maybe fixedly mounted and the desired separation secured by movement of the other. The invention also comprises the use of any meansior mounting the transparent'walls in a manner permitting their outward movement, and while the invention'comprisesthe means for causing their separation under-the pressure-applied to the liquid admitted between the walls, the admis sion of the liquid may beeffec'tedby movement imparted" to the walls, and the liquid may pass into position between the transparent walls under pressure normally maintained, or by gravity, or the pressure may be-applied upon the gaseous or liquid medium simultaneously with movement imparted to the movable transparent walls.

As represented, for example, in Figure 8, one of the transparent plates at is'of fixed position in a suitable mount 19, while the other of the plates a. is movable relatively thereto and for the purpose is carried in amount q which is connected to the mount p by a flexible element forming the closure of the cavity between the edges ofthe plates. The mount q is provided at intervals around the periphery with studs which extend through inclined slots T provided in an operating element 1" formed as a ring which is rotatable through a certain. angle with respect to the mount q, such rotation being eiiected by suitable means. Thus it will be understood that the admission of the gaseous or liquid medium into position between the transparent walls may be eifected from a relatively distant point. Or again the reservoir or container for the gaseous or liquid medium i may be disposed adjacent the transparent walls,

andthecontrol of movement of the transparent walls may be effected by mechanical, hydraulic or'pneumatic means, a simple method being Bowden or other similar transmission wire. A series of transparent walls may be provided so' mounted that'cavities may be providedbetween them within which a liquid or gaseous'medium such as hereinb'efore described may be admitted.

It'will be understood that in the use of liquid a colour soluble in the liquid used may be employed that'is adapted to dim the light transmitted through it to the extent desired, whereby only part of the light from the sourceis transmitted. It will'beunderstood that colours soluble in the liquid used areadvantageously employed.

No limitation is involved to any particular colours, nor yet to the" particular density'of the colour or optical'efiects secured, Furthermore no limitation is involved 'to the particular means of mounting the transparent walls within an elastic packing, nor yet to the shape of the walls. It is, however, preferred to employ elastic or india rubber packing, such as hereinbefore described in which grooves are moulded in the packing for the insertion of the edges of the walls" or plates of 1 glass or other material employed} These grooves maybe provided of an angular section corresponding to' the form of the edge of the glass walls or plates employed, the angular section at the edge being soformed in relation to the secticn of the groove'tha't while the glass orplate may be readily insertedso that its edges are inserte'd inthe elastic packing, a perfectly liquid or gas tight joint is thus provided. It will, however, be understood that any other means of providing a gasor liquidtight joint may be employed that will, permit of the relative movement of the t'rans parent walls or plates employed.

The invention however comprises the alterna.-

tive of. rendering an intermediate transparentwall 1 or plate movable; while mounting the outer transparent .walls orplatesfimmo'vable. In this way thei-ntermediatewall or plate may be mounted by flexible means in the manner of a diaphragm, the intermediate wall or plate being mounted within .the frame to whicha jfiexible gas, or liquid tight material is connected, theouter end of which is similarly secured to the surrounding frame. Any other means of mounting the respective fixed and movable transparent walls or plates may be employed. The transparent walls or plates maytakethe form of lenses or .sheets of glass having plane faces.

1. In an intensity control meansfor light, the combination of a pair .of transparent juxtaposed plates arranged substantially parallel to each other, a yielding seating member for receiving the edges of-said plate to form a seal about the edges thereof and for yieldingly urging said plates toward each other with a sufficient force to move the same into enga'gementwith' each other,.and'fiuid pressure means for introducing fluid under pressure between said plates'forfilling, the space between said'plates with a' fluid and for moving said plates away from each other to vary the thickness of the fiuidlayer therebetween. v v I s 2. In an intensitycontrol means for light,the

combinationof a pair of similarly shapedtransparent plates arranged in juxtaposed contacting relation with each "other; a substantially imper forate peripheral' member of relatively high yielding properties embracing the edges of said plates andforming a seal toprevent-lluid which may be introduced between said plates from being lost but at the same time permitting said plates to be yieldingly moved away from, each other against theresilient action of said member which embraces said edges and holds said plates normally in engagement with each other, and means for introducing fluid under pressure between said plates to move said plates outwardly away from each other against the action of said resilient means. 7

3. In an intensity control means for light, the combination with a pair of transparent plates, of a relatively soft pliable imperforate yielding member grooved to receive the peripheral edges of said plates and form a seal therefor, said yielding member also having suiflcient resiliency to urge said plates normally into contact with each other, a fluid pressure conduit leading through said member, and a fluid pressure supplying means for supplying fluid under pressure to said conduit whereby the fluid under pressure enters between said plates and moves said plates away from each other, said fluid which is introduced between said plates having light modifying propensities.

4. In a light modifying device, the combination with a plurality of transparent plates set in juxtaposed positions and through which the light is directed, a seating element inwhich said plates are mounted to be relatively movable in a direction toward and from each other, a fluid medium supplying means for supplying fluid medium between said plates and for forcing said plates away from each other, and a pressure creating means operatively connected with said fluid medium supplying means movable to an operative position in which a predetermined amount of the fluid is between the transparent plates and to another position in which a lesser quantity of fluid is between said transparent plates, operator-controlled meansfor moving said pressure creating means to and from either of said positions, and means automatically operable for insuring that said pressure creating means is moved to and held in either one or the other of said positions and no other after said operator-controlled means is actuated to move said pressure creating means to a position in proximity to either of said positions.

5. In a light modifying device, the combination with a plurality of transparent plates set in juxtaposed positions and through which the light is directed, a seating element in which said plates are mounted to be relatively movable in directions. toward and from each other, means for supplying a fluid medium between said plates to spread said plates and occupy the space therebetween, a container for the fluid connected to said seating, a flexible diaphragm in said container forming with a portion of the container a variable sized chamber, a control element for moving said diaphragm to change the size of said chamber to move liquid out of and into said chamber and container, and a yielding element for moving the control element to either of two different limiting positions of its permitted movement.

6. In a light modifying device, the combination with a plurality of transparent plates set in juxtaposed positions and through which the light is directed, a seating element in which said plates are mounted to be relatively movable in a direction toward and from each other, means for supplying a fluid medium between said plates to spread said plates and occupythe space there between, a receptacle for the fluid medium, means for moving a predetermined quantity of the fluid medium out of said receptacle and for drawing the fluid medium back into said receptacle, a yielding element for holding said last mentioned means either in the position which it occupies when said predetermined quantity of fluid is out of said receptacle or in the position which it occupies when the same predetermined quantity of fluid has been withdrawn into said receptacle, and means connecting said receptacle with said seating and the edges of said plates whereby said predetermined quantity of fluid is moved between said plates and removed therefrom as desired.

7. In a light modifying device the combination with a plurality of transparent plates arranged in substantially parallel relation with each other with their flat sides in contact with each other, the adjacent faces of said plates at their edges being beveled to form a fluid receiving recess between said plates at their peripheries, a sealing member for sealing said fluid receiving space and for urging said plates into contact with each other, and fluid pressure means for supplying fluid under pressure to said fluid space to move said plates away from each other and permit the fluid to enter the space therebetween.

8. Means adapted to control the intensity and color of projected and transmitted light, comprising a plurality of transparent plates set in juxtaposed contacting relation with each other and through which the light is to be directed, a resilient seating element in which said plates are mounted for relative movement in directions toward and fromeach other, means for directing a fluid medium between adjacent transparent plates to spread said plates and occupy the space therebetween, and means for forcing said fluid medium through said directing means to a position between said plates, whereby the fluid pressure moves said plates away from each other.

9. Means adapted to control the intensity and color of projected and transmitted light, comprising a plurality of transparent plates set in juxtaposed contacting relation with each other and through which the light is to be directed, a resilient seating element in which said platesare mounted for relative movement in directions toward and from each other, means for directing a fluid medium between adjacent transparent plates to spread said plates and occupy the space therebetween, and means for forcing said fluid medium through said directing means to a position between said plates, whereby the fluid pressure moves said plates away from each other, comprising a fluid chamber and fluid moving means in said chamber having means associated therewith for normally holding said fluid moving means in either of two positions when manual pressure on same is released whereby a predetermined quantity or" fluid will be discharged from said chamber and directed into the space between said plates when said moving means is moved to one of its positions and will be withdrawn into said chamber upon movement of said moving means similar but opposite positions, a diaphragm extending across said chamber and connected with said plate to move therewith, whereby upon release of said plate said plate as well as said diaphragm will be moved into one of said two opposite positions within said chamber to vary by predetermined amounts the size of the fluid receiving portion of said chamber.

GEORGE KE'ITELWELL HARKNESS. JOHN MAXWELLHARKNESS. 

